Bipyridine-N,N′-dioxides Catalysts: Design, Synthesis, and Application in Asymmetric Synthesis of 1H-Pyrazolo[3,4-b]pyridine Analogues
作者:Shijie Zhu、Xue Tian、Jichang Liu、Bin Dai、Shi-Wu Li
DOI:10.1021/acs.orglett.4c00515
日期:2024.5.3
A novel type of highly efficient chiral C2-symmetric bipyridine-N,N′-dioxidesligand application in catalyzing Michael addition/Cyclization of 5-aminopyrazoles with α,β-unsaturated 2-acyl imidazoles has been developed, affording the corresponding adducts in 85–97% yield with up to 99% enantioselectivity under mild conditions with a lower catalyst loading and broad scope. Remarkably, this protocol exhibits